Matrix band forming template



Nov. 10, 1964 F. J. zoLNowsKl 3,156'049 MATRIX BAND FoRMING TEMPLATEFiled March 21, 1982 United States Patent O 3,156,049 MATRIX BANDFORMING 'EEM'PLATE Frank 29'. Zolnowshi, 34% E. Pianhinton Ave., Cudahy,Wis. Filed Mar. 21, 1962, Ser. No. 181,286 7 Ciaims. (Ci. 33-174) Thisinvention relates to a templtae for forming matrix bands of the typewhich are looped around the tooth to be filled or restored and thentightened to closely conform to the irregular axial Contour of thetooth.

Matrix hands of this general Character are preferably Curved lengthwisewhen the band is fiat so that the band will become generallyfrusto-conical in shape when it is looped and drawn tightly around thetooth. Strated otherwise, the Curved or generaliy arcuate shaped flatband will insure that the band will adapt itself snugly around the toothat the gingival portion or gum line and then flare outwardly occlus'aliyto facilitate proper restoration of the Crown portion of the tooth.

Heretofore, hands of this type have been formed' by Cutting the bandfrom a flat piece of steel matrix ribbon or the like to form a generallyCurved and fiat band. This has proved to be not entirely satisfactorybecause the shape and size of the hands varied considerably with theskill of the dentist in Cutting out the band. In other words, such bandsoften did not have the correct curvature that would result in a properfrusto-conical shape when looped around the tooth and which is necessaryif the band is to adapt itself properly to the Contour of the tooth.Generally stated, these b'ands would flare excessively in an occlusaldirection and therefore be incapable of adapting themselves to theContour of the tooth at the Crown portion. In other cases, these bandswould not have sufficient taper when looped around a tooth to insure asnug fit around the gingival portion. Furthermore, these prior :artb'ands would be either too narrow, that is of insucient height, toentirely enclose the height of the cavity and thereby retain the matrix,or they would have too much height and thereby prevent proper andcomplete alignment between opposing teeth when the jaws of the patientwere closed, as when a Wax pattern for gold inlays was being forrned inthe Cavity.

Bands of this general nature have also heretofore been formed fromconventional steel matrix ribbon by simply folding a length of theribbon over itself along a line inclined to the length of the ribbon,which would result in bands of generally arcuate or Curved shape. Thistype of folded band has heretofore not been generally acoepted becauseof the difficulty in forming it, and often requiring additional Cuttingwith scissors in order to give it the proper general curvature. ln otherwords, it has been diificult to consistently and accurately bend theribbon over itself at the proper 'angle to thereby result in a properlyCurved band. When such a band was looped and tightly drawn around thetooth, an improper degree of flare and consequently an improperlyfitting band resulted.

in addition, these folded type of bands were often unsatisfactory,because the resulting short height in the band which occurred in thecenter of the folded or double thickness portion of the band would notalways be formed in the Center of the length of the completed band. Inother words, the Center of the folded portion Could not always andaccurately be formed in the Center of the length of the band. As aresult, that portion of the folded band which was narrower in width thanthe remainder of the band could not be positioned in the center of thelingual side of the tooth where it is most desirable to locate it.Stated otherwise, the back or tongue Side of the tooth is where lessband height is ordinarily needed in order to completely and accuratelyconfine the matrix, and it is Zidii Patented Nov. 10, 1964 ICC thereforedesirable, when using a folded type of band, to position the narrowheight portion of the band in the middle of that back or lingual side ofthe tooth.

Accordingly, the present invention relates to a template for forming -amatrix band by folding the band over itself and into a flat andgenerally Curved band. More spe- CifiCally, the template provided by thepresent invention forms an accurately Curved matrix band having aportion of less width located generally centrally of the length of thecompleted band. This portion of less width Can thereby be positioned inthe middle of the lingual surface of the tooth. Furthermore, the bandformed by means of the present invention assumes the properfrusto-Conical Shape when tightened around the tooth to thereby resultin a snug fit around the gingival portion of the tooth and a properlyfitting occlusal portion around the Crown portion of the tooth.

A more specific aspect of the present invention relates to a template ofthe above type which has measuring means for determining the properlength of ribbon to be cut from a stock roll in accordancewith the typeof tooth to be worked on and/or in accordance with the type of holder tobe used to tighten and hold the band.

Furthermore, the invention contemplates that the template has indiciafor properly positioning the ribbon on the template and in respect to afolding edge thereof; so that portion of least width of the folded bandis Vlocated Centrally of the length of the finished band. i

More specifically, the present invention relates to a template of theabove type having a folding edge over which the band is folded, and alsohaving a guide edge which positions the band at the proper anglerelative to the folding edge, so as to result in .a accurately foldedband of proper general curvature when flat.

Another more limited aspect of the invention relates to making the topedge of the'template of a Shape coinciding with the shape of thefinished band, whereby a check may be made as to the correctness of thefinished band.

Still another aspect of the invention relates to a template of the abovetype which also has a burnishing edge whereby the burnishing operationon the band being formed Can be accomplished with the same template.

These and other objects and advantages of the invention will appearhereinafter `as this disclosure progresses, reference being had to theacconipanying drawings, in which:

FIGURE l is a general view of a template made in ac- Cordance with thepresent invention;

FIGURE Z is a sectional view taken along line 2-2 in FIGURE l, but on anenlarged Scale;

FIGURE 3 is a view similar to FIGURE l, but showing a band placed on.the template and in position just prior to folding it over the top edgeof the template;

FIGURE 4a is a side view of a folded band, on an enlarged scale, andbefore burnishing has been completed, and showing the template in theposition and in the direction it is swingable or rockable for thepreliminary burnishing operation, that is, for initially ironing orfiattening the folded band; i

FIGURE 4b is a view similar .to FIGURE 4a, but showing the template usedwith a sliding movernent across the band, as during 'the finalburnishing operation, the template 'being held more or less normal tothe band; v v

FIGURE 4 is a plan view of the band shown in FIG- URES 4a and 4b butafter it has been burnished;

FIGURE 5 is a perspective view of the band about to be placed around atooth and in a Wagner type matrix holder;

FIGURE 6 is a plan view of the band around the tooth and showing theWagner holder in the tightened position;

FIGURE 7 is an elevational view of the lingual side of 3 the tooth andtaken generally along line 7-7 in FIG- URE 6;

FIGURE 8 is a view similar to FIGURE 4, but showing a band folded at anangle which is too acute to give the proper general curvature to theflat, folded band;

FIGURE 9 is an elevationm view of a completed band formed from theFIGURE 8 band;

FIGURE 10 is a view also similar to FIGURE 4, but of a band folded at anangle which was too obtuse to result in a band of proper generalcurvature; and

FIGURE 11 is an elevational view of a completed band formed from theFIGURE 10 fiat band.

The conventional steel matrix ribbons on the market today, and fromwhich matrix bands are formed, are made in various widths, for example,3AG, 1/4, W16, 3/s, and 7/16 of an inch. These ribbons are on the orderof .002 of an inch in thickness. Generally speaking, the most commonlyused widths are the narrower ones mentioned and provide suflicientheight to the completed frusto-conical band, in the great majority ofcases, to retain the matrix in the tooth.

Portions of these ribbons are cut from the stock roll of the ribbon asneeded, and it is desirable not to waste the ribbon by cutting offportions that are unnecessarily long or by making several improperlyformed ribbons before a good one is finally fashoned.

The wider bands are used rather infrequently and for situations in whichwork must be done on the tooth below the normal gum line or in caseswhere certain portions of the band must be cut away to accommodate thegum, other teeth, or other obstacles in the month.

The template made in accordance with the present invention providesameans for making hands with the most economical use of metal ribbon andlimits the waste thereof to a minimum. Only enough ribbon material iscut from the stock roll to accommodate the type of tooth being worked onand the particular holder for holding the band. It will be appreciatedthat different types of holders are useable with the present invention,such as, for example, the Tofiiemire holder shown in US. Patent No.2,538,486, or the Wagner matrix holder of the type shown in thisapplication. Generally speaking, the Wagner type of holder is preferablebecause it is considerably smaller and less obstructive and permits thepatient to '*bite more easily during the tooth restoration process.

Referring more specifically to the drawings, the template T may beformed from a piece of sheet metal 1' or other suitable material and isshown as being generaliy rectangular in Shape and prefera'oly having theupper corners cut away for purposes that will appear hereinafter,although other shapes may be used if desired.

Generally, there are two types of teeth with which the present apparatusmay be used, namely, the bicuspid and the molar, and a matrix band ofone particular length would be suitable for the molar of a small childand also suitable for the bicuspid of an adult. Similarly, a matrix bandof one particular length would be useable for the molar of a child aswell as for an adulfs molar. Therefore, for the majority of widths ofhands used, only two classifications of lengths are necessary, namely, abicuspid length and a molar length.

M easurng Means Referring again to FIGURE 1, the numeral B designatesthe general length from the righthand edge 1 of the template to whichthe ribbon should be cut if a bicuspid is to be worked on. Similarly,the reference numeral M inscribed near the lower edge of the templateindicates the general length from the righthand edge 1 of the templateto which a ribbon should be cut if a molar is to be worked on. Theselengths are fairly accurate and average, assuming that the Wagner typeof holder is to be used, and the length B for example may heapproximately 42 millimeters, and the length M may be 54 millimeters.

If a holder is to be used which requires a longer band for grippingpurposes, such as the Tofiiemire holder previously referred to, then alength of ribbon of approximately millimeters from the righthand edge 1of the template to the indication marked X adjacent the lower edge ofthe template would be necessary, for either a molar or bicuspd.

As shown in FIGURE 1, the ribbon R has been placed along the measuringmeans prior to its being torn along edge 1. The matrix band MB so cut ortom along edge 1 is shown in FIGURE 3.

The rest of the bottom edge of the template may be also graduated intomillimeter markings as indicatcd, in order that the doctor may have anadditional convenieut indicationV for measuring the length of ribbondesired for any particular use, in the event the main markings B, M, andX were not suitable.

Thus, the lower edge of the template forms a measuring means 2a alongwhich the ribbon is laid before being cut and with the free end of theribbon located at its proper reference point; the ribbon is then cut atthe extreme right edge 1 of the template as by tearing it along theedge 1. Thus, a convenieut measuring means is provided for cutting off aband MB from the stock roll of ribbon R with a minimum of waste.

Obviously, other measuring means may be provided on the template, andspecific measuring marks as above indicated need not be employed.Instead, the template itself may be of such a length so as to serve as ameasuring indication of the length of band to be cut from the stockroll. Experience may dictate to the user just what the length of bandshould be relative to the length of the template or markings thereon,for a given type of tooth or restoration.

Band Foldng Edge A fo'lding edge 3 is provided along one side of thetemplate, and it is over this edge that the band is tightly folded over.This edge should be straight and of a Sailicient length to fully supportthe entire width of any size bands useable for this work.

Band Guide Mteans Means are provided to properly position the straightband MB on the template and at the proper angle in respect to thefolding edge 3 so that the flat band when folded over itself has theproper degree or amount of general curvature. As examples of foldedbands of various general curvatures, a properly folded band is shown inFIGURE 4, a band having a fold that is too acute is shown in FIGURE S,and a band that has a general curvature that is too flat is shown inFIGURE 10.

This means for insuring the proper angle of bend to the band, andconsequently a proper general curvature, takes the form of a guide edge4 which may comprise a straight strip of steel or other material that iswelded or otherwise seeured to the face of the template. This guide edged forms an acute angle of approximately 19 degrees with the folding edge3, and it has been found that this approximate angle provides a foldedband of the most desirable general curvature for a matrix band.

As shown in FIGURE 4, the narrowmost portion 5 of the band is located inthe doubled over portion thereof. It is important that this narrowmostportion is located approximately centrally of the length of the foldedband, for reasons that will hereafter appear more fully. In order toinsure that this narrowmost portion is so disposed relative to thelength of the band, indicia b, m, and x are inscribed on the templateand adjacent and along the guide edge 4. The small reference letters b,m, and x correspond to their capital letters counterparts B, M, and Xlocated along the measuring means and are correlated therewith. If thedimensions for the lengths B, M, and X which were previously referred toare used, then the suitable dimensions for the distances from the smallletters reference marks b, m and x along the guide edge 4 and to theintersection of the folding edge 3 Would be as follows. The distancefrom b to edge 3 should be approximately 30 millimeters; from m to edge3 would be about 34 millimeters; and from mark x to edge 3 about 40millimeters. With marks B, M, and X so correlated with marks b, m, andx, the folded area of the finished band will be located substantiallycentrally of the length thereof.

Assume that a biscuspid band MB has been cut by measuring from therighthand edge ll of the template up to the mark B. That piece of bandwould then be placed tightly along the guide edge 4 so that one end ofthe band is in alignment with mark b, and the free end of the bandextends beyond the folding edge 3.

Similarly, if a molar is to be restored, the M measuring mark would beused to determine the length of a band. In that case, reference m wouldalso be used adjacent the guide edge 4 to axially position thatparticular bmd relative to the folding edge 3. The mark X on themeasuring means is correlated with the mark x on the guide means forbands which are to be used with the Tofilernire type of holder mentionedin the above patent.

Thus, the indicia along the guide edge serves to axially position theband relative to the folding edge 3.

Fold and Burnshz'ng the Band Referring now to FIGURE 3, when the band MBhas beenpositioned with one of its ends coincident with the mark b, theuser tightly holds the band against the guide edge 4 and simultaneouslyrolls or folds the band tightly over the folding edge 3. This resultsgenerally in a folded band, as indicated in FIGURE 4a, with that portionof the band at the fold area being of double thickness.

The folded area is then compressed or burnished with any convenient hardtool or with the template itself as will be described, so as to reducethe overlappedarea 5 to approximately only one thickness of metal asshown in FIGURE 4b. This insures that the band will wrap around thetooth without kinking or buckling to any appreciable extent.

The burnishing operation may be performed by the template itself byusing the rounded lower edge 9 of the template, as indicated in FIGURES4a and 4b. This rounded, burnishing edge of the tool is formed on thellower edges of the strip 2, the template itself, and another strip 10which is welded or otherwise formed along the lower, rear side of thetemplate.

As indicated in FIGURE 4a, the preliminary burnishing operation isaccomplished by more or less rocking the template over the foldedportion of the band and against any convenient hard surface, so as tosubstantially fiatten the folded area. FTGURE 4b illustrates the finalburnishing operation which consists of forcing the rounded edge downfirmly on the band and then sliding the template back and forth over thefolded area. This results in a band of practically uniform thicknessthroughout its length and one which bends uniformly around the tooth.

General It should also be mentioned that the templates shown in thepresent application is satisfactorily used with the narrower types ofribbons above referred to, and if wider ribbons are to be used, atemplate having different measuring indicia thereon may be desired. ltwill be appreciated that the measuring indications along one edge of thetemplate and the indicia along the guide edge may vary, for example withthe width of band used, and the hands need not be cut exactly to length.Nevertheless, a correlation between the length of unfolded band and itsposition in respect to the folding edge 3 over which it is to be foldedis important.

FIGURE 5 shows the band when its free ends have been inserted in theWagner holder and when the adjusting nut 4' has been only preliminarilytightened to leave the loop formed by the band sufiiciently large toslip over the tooth T' to be worked on. The free ends of the band areheld firmly in the holder by the sharp pins dc and 4d which puncture theband ends. After the band is slipped around the tooth, the nut 4' istightened additionally to draw the band ends further into the holder andtightly around the tooth, as shown in FIGURE 6.

As shown in FIGURE 7, the band MB formed on the present template resultsin a frusto-conical shape when looped around the tooth and which closelyfollows the axial Contour of the tooth. The shape is such that thenarrow end of the frusto-conical cone snugly fits around the ginivalportion of the tooth, and the other end of the frusto-conical bandwidens occlusally to closely follow the Contour of the crown portion ofthe tooth.

The position of the band on the tooth in regard to the height thereof isdetermined primarily by the type of work to be performed on the tooth.For example, for amalgam work, such as if a silver filling is to beplaced in the cavity of the tooth, the band can be set rather high onthe tooth, even higher than that shown in FIGURE 7, so long as thecavity portion thereof is completely confined by the band. Once thesilver filling has been packed in the cavity and the band then removed,the filling can be sculptured to the exact Contour of the tooth desired.

FIGURE 7 shows the top of the band positioned about level with the topof the tooth which is a desirable position for inlay work. For example,if a wax pattern is to be made of the cavity for a gold inlay, then theband would be positioned on the tooth asshown in FIGURE 7 to permit afunctional bite to be taken prior to theI carvmg.

For either of the above-mentioned type of tooth restoration work, theband provided by the present invention forms a desirably shapedfrusto-conical band which closely follows the axial Contour of the toothand one in which the narrow portion 5 of the folded band is located onthe lingual surface of the tooth where maximum band height is notnecessary to insure confinement of the matrix.

FIGURE 8 illustrates a band that has been bent over itself at an anglewhich is too acute, thereby resulting in a frusto-conical Shape havingtoo much flare, as shown in FIGURE 9. This type of improperly formedband Would result in escape of or excessive matrix at the crown portionof the tooth.

FTGURE 10 shows a band that has also been improperly formed because oftoo fiat an angle of fold. This results in a frusto-conical cone (FIGURE11) havlng sides that are too steep to permit the band to tightly abutagainst the gingival portion of the tooth, resulting in an escape of thematrix at this gingival portion.

Means are also provided on 'the template for checking the generalcurvature of the completed band so as to be sure it is correct. Thismeans consists in removing the upper corners of the template so as toform the inclined edges 12 and 13. The three edges 3, 12, and 13together form a pattern which the finished band should duplicate. Thus,when the band is finished, it is laid along on the back side 14 of thetemplate and along the edges 3, 12, and 13 so that the upper edges ofthe band coincide with edges 3, 12, and 13. This forms a convenient,quick, and accurate means for checking the correctness of the generalcurvature of -the finished band.

The distance between the guide edge 4 and the parallel edge 12 ispreferably 5/10 of an inch which will conveniently accommodate bands ofup to 5/16 of an inch, 5/16 of an inch being the maximum average widthused in the majority of situations.

The template provided by the present invention is fiat and small in sizewhich can be kept conveniently With other tools of the dentist, andprovides an eflicient and effective means for repeatedly, quickly,economically, and accurately forming matrix hands of ideal curvature.

Various modes of carrying out the invention are con- 7 templated asbeing within the scope of the following claims particularly pointing outand distinctly claiming the subject matter which is regarded as theinvention.

I claim:

1. A matrix band forming template for guidng a band which is beingfolded over itself into a generally curved and flat band, said templatebeing a generally flat and unitary member and having one side defining afolding edge over which said band is foldable, a guide edge formed onthe template and arranged at substantially less than a forty-five degreeangle with said folding edge and for guidng and positioning said band atthe proper angle relative to said folding edge, and type of toothindicia along said guide edge and spaced a predetermined distance fromthe intersection of said folding edge and said guide edge fordetermining the proper axial position of said band relative to saidfolding edge to thereby substantially center the finished fold on saidband.

2. In a matrix band forming template for guidng a band while beingfolded over itself into a generally curved and fiat band having acentral folded portion, said template being a generally fiat and unitarymember, said template having means for measuring a band length, one sideof said template defining a folding edge over which said band isfoldable, a guide edge formed on the template and arranged atsubstantially less than a fortyfive degree angle with said folding edgeand for guidng and positioning said band at the proper angle relative tosaid folding edge type of tooth, and indicia along said guide edge andspaced a predetermined distance from the intersection of said foldingedge and said guide edge for determining the proper axial position ofsaid band relative to said folding edge, said measuring means beingcorrelated with said indicia for a given length of band to therebyinsure that said folded portion is located generally centrally of thelength of the folded band.

3. A matrix band forming template for guidng a band while being foldedover itself into a generally curved and flat band, said template being agenerally flat and unitary member having one side comprising a foldingedge over which said band is foldable, and a guide edge formcd on saidtemplate and arranged at an acute angle of approximately 19 degrees withsaid folding edge for guidng and positioning said band at the properangle relative to said foldin g edge.

4. A matrix band forming template for guidng a band which is beingfolded over itself into a generally curved and flat band, said templatebeing a generally flat and unitary member having means for measuring aband length, one side of said template defining a folding edge overwhich said band is foldable, a guide edge formed on said template andarranged at an acute angle of approximately 19 degrces with said foldingedge for guidng and positioninO said band at the proper angle relativeto said folding edge, and indicia along said guide edge for determiningthe proper axial position of said band relative to said folding edge.

5. In a matrix band forming template for guidng a band While beingfolded over itself into a generally curved and fiat band having acentral folded portion, said template being a generally fiat and unitarymember having means for measuring a band length, one side of saidtemplate (lefining a folding edge over which said band is foldablc, aguide edge formcd on said template and arranged at an acute angle ofapproximately 19 degrees with said folding edge for guidng andpositoning said band at the proper angle relative to said folding edge,and indicia along said guide edge for determining the proper axialposition of said band relative to said folding edge, said measuringmeans being correlated with said indicia for a given length of band tothereby insure that said folded portion is located generally centrallyof the length of the folded band.

6. A generally fiat dental band forming template for guidng a steelmatrix band while the latter is being folded over itself at an angle `toits length and into a generally curved and flat band having a generallycentral folded portion, said template being a generally fiat and unitarymember having a generally flat front surface, said template alsoincluding means for measuring a length of steel matrix ribbon to besevered into band of definite length, a straight and thin folding edgealong one side of said template and over which said severed band isfoldable, a straight guide edge formed on said surface and arranged atan acute angle of generally 19 degrees with said folding edge, said bandabuttable along said guide edge for being positioned at the proper anglerelative to said folding edge for subsequent folding thereover, andindicia along said guide edge for determining the proper lengthwiseposition of said band relative to said folding edge.

7. A generally flat dental band forming template for guidng a steelmatrix band while the la'tter is being folded over itself at an angle toits length and into a generally curved and fiat band having a generallycentral folded portion, said template having a generally fiat frontsurface and also including means for measuring a length of steel matrixribbon to be severed into band of definite length, a straight and thinfolding edge along one side of said template and over which said severedband is foldable, a straight guide edge on said surface and arranged atan acute angle of generally 19 degrees with said folding edge, said bandabuttable along said guide edge for being positioned at the proper anglerelative to said folding edge for subsequent folding thereover, andindicia along said guide edge for determining the proper length- Wiseposition of said band relative to said folding edge, said measuringmeans being correlated with said indicia for a given length of band tothereby insure that said folded portion is located generally centrallyof the length of the folded band.

References Cited in the file of this patent UNITED STATES PATENTS207,288 averty Aug. 20, 1878 386,718 Reardon July 24, 1888 1,164-,844Mudge Dec. 21, 1915 1,619,427 McCaffery Mar. 1, 1927 2,466,830Tofliemire Apr. 12, 1949

1. A MATRIX BAND FORMING TEMPLATE FOR GUIDING A BAND WHICH IS BEINGFOLDED OVER ITSELF INTO A GENERALLY CURVED AND FLAT BAND, SAID TEMPLATEBEING A GENERALLY FLAT AND UNITARY MEMBER AND HAVING ONE SIDE DEFINING AFOLDING EDGE OVER WHICH SAID BAND IS FOLDABLE, A GUIDE EDGE FORMED ONTHE TEMPLATE AND ARRANGED AT SUBSTANTIALLY LESS THAN A FORTY-FIVE DEGREEANGLE WITH SAID FOLDING EDGE AND FOR GUIDING AND POSITIONING SAID BANDAT THE PROPER ANGLE RELATIVE TO SAID FOLDING EDGE, AND TYPE OF TOOTHINDICIA ALONG SAID GUIDE EDGE AND SPACED A PREDETERMINED DISTANCE FROMTHE INTERSECTION OF SAID FOLDING EDGE AND SAID GUIDE EDGE FORDETERMINING THE PROPER AXIAL POSITION OF SAID BAND RELATIVE TO SAIDFOLDING EDGE TO THEREBY SUBSTANTIALLY CENTER THE FINISHED FOLD ON SAIDBAND.